Foam the interior.or even all the way to the exterior.then fabricate a cover for the exterior and caulk or use duct seal around the lines.
How Do You Cover Up A Hole In The Wall. If you have a hole in the wall right above, below, or beside a window, try replacing your current window treatment with a larger one that covers the hole. I've repaired a lot of holes in my time.
How to fix a poor mud job on an already painted interior ... from qph.fs.quoracdn.net
Decorating your walls can be a pain in the ass, but it's not so bad once you get the hang of it. These are sometimes covered with plastic or have screws already in. Whether you need to create privacy, conceal damage, block light or add wall space, it is possible to permanently cover a window in a way that no one will know that a window was ever there.
You can use soundproof curtains to cover the hole in your wall as well.
This will make your posters easier to work with since the edges won't be curling back up as much. It depends what the wall is made of and how big the hole is. Get the hole fixed as soon as possible. This is a loaded question.